Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/71

Rh not as a figure of speech, but as measured by the thermometer, as that of Moscow is below that of Edinburgh.

Daily Range of Temperature.—We have been speaking so far entirely of what tables of temperature usually deal with, mean temperatures month by month in the shade. We have said nothing at all of the range of temperature during each day, and must next direct our attention to this. The following table, thanks to the very valuable set of observations conducted under Mr. Sopwith's auspices, will tell us substantially all that we need to know here. For By well and Allenheads it gives in the first column the average excess, month by month, of the daily maxima in the sun over those in the shade, in the second the average fall of the nightly minima on the grass below those of the air, in the third the average daily range in the shade; and if we add these three figures together we shall get, in the fourth column, the total daily range to which a plant will be exposed at the surface of the soil, day by day, when it grows in an unsheltered position.